Geology of the Isle of Wight

Rocks of Devonian, Triassic and Jurassic age are known to be present in the subsurface of the island from boreholes and interpreted seismic reflection profiles.

[1] The Wessex Formation consists of red mudstones with some interbedded sandstones laid down in a freshwater and floodplain environment.

The Vectis Formation consists of grey mudstones, deposited in a shallow water lacustrine to lagoonal setting, with some evidence of marine influence.

[1] Rocks of Palaeogene age rest unconformably on the Upper Cretaceous sequence on the Isle of Wight.

[1] The Palaeogene strata were deposited in a shallow water marine environment, which was affected by repeated changes in relative sea level, causing cycles of transgression and regression.

[1] On the Isle of Wight this group comprises the Ypresian (lowermost Eocene) London Clay Formation, which reaches up to 160 m in thickness.

Reactivation of these faults over part of their lengths during the Paleogene inversion event produced the structures that control the current outcrop patterns.

Geological map of the Isle of Wight
Ferruginous Sands Formation of the Lower Greensand Group exposed in the sides of Whale Chine
Sandstones of the Upper Greensand Formation above Blackgang
The cliffs of Alum Bay showing the almost complete Palaeogene section on the Isle of Wight. The monoclinal nature of the structure is shown by the decrease in dip towards the north
The Headon Formation with Bembridge Limestone Formation to the right and the upper part of the Barton Group to the left in the cliffs of Whitecliff Bay
Scratchell's Bay showing northward increase in dip towards the Isle of Wight monocline